Filter assembly



Oct. 25, 1938. A MUNOZ 2,134,413

FILTER ASSEMBLY Filed May 20, 1937 nllll Patented oef. 25, 193s UNITED STATES PATENT OFFICE 2,134,413 mma ASSEMBLY Alfred Munoz, Brooklyn, N. Y. Application May zo, 1931, serial No. 143,661

6 Claims.

The invention here disclosed relates to filters of the type employed in mechanical refrigerator systems.

Objects of the invention are to provide a filter assembly of simple inexpensive construction. consisting of but few. easily assembled parts; which will serve without attention over long periods of use and which when required may be readily taken apart and easily cleaned; which may when l0 required be used in the capacity of a check valve as well as filter and which further, -if desired, may be employed as a unit for restricting and smoothing the flow of the chemical employed as the refrigerant.

ll @The foregoing and other desirable objects are attained in this invention by the novel features of construction, combinations and relations of parts hereinafter described, illustrated and broadly claimed.

A The drawing accompanying and forming part of the following specication illustrates several practical commercial embodiments of the invention, but these are primarily illustrative in character, it being appreciated that changes and modification in structure may be made within the true spirit and scope of the invention as hereinafter defined and claimed.

Fig. 1 is a broken longitudinal sectional view of one of the lter assemblies. Fig. 2 is a broken part sectional detail of another embodiment.

Fig. 3 is a similar view of a further modication.

The shell or casing of the 'llter is shown as mad@ up as a/ hollow body member 5, and a tubular \over` l,l screwed into the open end of the same with a lead gasket or other suitable seal, such as indicated at 1. 'I'hese body and cover portions are shown as having screw nipples 8, 9, 40 byr which the lter may be connected in line with the evaporator and condenser elements of the reiiector system. v

In the present illustration, Fig. 1, a coil of capillary tubing I0, is directly connected with and made a part of the lter by the coupling Il, engaged with screw nipple 8, said coil carrying at its opposite end a similar coupling I2, or equivalent by which the latter end of the coil may be connected in the line leading to the evaporator. The filter element is indicated at I3, as a stack of washers or discs spaced to admit the liquid being ltered, the filter leaves thus provided being conned between end plates Il, I5, loosely h d together by a rivet or stud I6, headed ,ove at opposite ends.

The end plate l5, of the filter element has a passage'or passages I1, to pass ltered liquid from inside the lter pile into the outlet channel I9. This washer seats flat against a shoulder I9, and is guided thereto by a rounded or tapered seat 20, l leading from the larger, chamber portion 2|, in the body to said shoulder.

A helical spring is indicated at 22, for holding the loosely retained pile of lter washers Ifirmly together, said spring bearing against the opposite closed end plate Il, and supported at its opposite end by the inner end of the annular screw neck portion 23. of the cap 6.

To protect the fine leaf filter from heavier parti' les and to prevent it from becoming clogged with accumulated matter, there is provided in the illustration Fig. 1, a thimble screen 2 4, having a ange 25, interposed between the end of the cap sleeve and the adjoining end of the spring 22. This screen, likethe lter element, is spaced from l0 the surrounding portions of the casing structure.

so as to provide ample exposed straining or filtering surface.

A back pressure valve is incorporated in the lter structure in the present disclosure as a ball check 26, held by spring 21, against the bevelled check valve seat 28, at the inner endof the inlet passage 29, in the covernipple 9.

In the Fig. 1 form of construction, the check valve spring 21, is shown as a short tapered coil 30 spring interposed between the ball valve 2B and the adjoining end of the thimble screen.

In constructions where the screen may not be considered as a necessary or desirable adjunct or guard for the edge filter element, a single spring 35 may be employed for holdingthe pile compressed and for thrusting the check valve to its seat. Such a construction is illustrated in Fig. 2, where a larger and longer coiled taper spring 21a is illustrated interposed directly between the end plate 40 Il of the filter and the check ball valve 26.

For some purposes, both the check valve and the screen may be considered unnecessary or unfdesirable and in such events, both the screen 2l and the check valve 26, may be omitted and a 45 spring such as 22, in Fig. l, be interposed between the iilter pile and end cap of the casing for simply holding the lter pile firmly in position in the casing.

The use of the screen as a guard for the filter 50 is particularly desirable for old refrigeration systems, where there may be considerable foreign matter in the refrigerant.

This construction then by straining out and keeping loose matter from reaching the lter, Il

enables a filter of standard size to be used where otherwise it might be necessary to employ an oversize filter assembly.

The iilter assembly may be readily taken apart by simply unscrewing the cap 6. This gives access to all interior parts, enabling the lter pile to be taken out, loosened and cleaned and the screen, if present, to be washed clean and similarly'the check valve, also if present, to be removed and cleaned as may be necessary.

The association of check valve, screen, iilter, pile and capillary tube, while desirable and cooperative in a complete assembly. is not essential, for as can be realized, one or more of such coacting elements may be eliminated and the structure still have commercial value. 'I'he check valve when the machine shuts down, holds pressure and prevents back rush of liquid through the capillary tube, thus maintaining the system at allA times in better operating condition.

The parts are few and of simple sturdy design, inexpensively manufactured and easily assembled or readily taken apart. The tapered extension leading to the seat for the lter pile enables the lter element to be readily centered by simply dropping it into the casing, after .which the force of the spring holds it in this centered relation with space all around for the liquid being filtered. The connection of the capillary coil directly to the end of the outlet nipple makes this coil in substance an integral part of the assembly, ready to be installed in the line between the evaporator and condenser, bracing and supporting this coil of light tubing in such relation.

To protect the check valve from matter which might hold it open, this valve may be located behind instead oi' in front oi' the screen, for example, between the screen and the lter pile, or as indicated in Fig. 3, in back of the iilter pile, as by locating it in the outlet nipple of the casing. In this relation, the liquid is strained before it reaches the check valve.

'I'he flange of the screen may be` in the form of a ring, such as indicated` at 30, Fig. 3, iltting into an annular seat 3|, in the cover. This ring is shown as having shoulderl 32, providing a seat for the end of the spring. This construction firmly locates the parts in their proper relations. Expansible spring washers of non-corrosive metal may b e used in place of the coiled springs shown and which usually are of steel and hence corrosible in certain of the refrigerant liquids now employed. 'I'he securing of the lter leaves in loosely assembled relation and using the spring to hold them closely assembled and properly seated in the filter chamber is advantageous from the manufacturing standpoint, also for assembling and particularly important for enabling quick cleaning. So far as known, the construction provides the iirst separable readily cleanable iilter for refrigerators, taking the place oi! the larger and more bulky non-separable lters made up of layers of telt and metallic screen in a two part shell, secured by a soldered joint. In cases where expansion valve is used instead of the capillary tube illustrated, the filter casing may be connected directed to the expansion valve or the iilter unitv be built in as a part of the expansion valve. The edge type iilter element in conjunction with the expansion valve lis much more eiilcient than the usual wire cloth screens heretofore employed in connection with expansion valves.

What is claimed is:

1. A refrigeration iilter comprising a casing having a `iilter chamber and a tapered extension from said chamber to a seating shoulder, a

iilter pile comprising a stack of filter leaves loosely retained between end plates, one end plate of a size to be guidedby said tapered extension to said seating shoulder, said casing having a. cover with an annular screw stem opposed to the opposite end of the seated iilter pile and a spring interposed between said screw stem and the opposite end plate of the filter pile.

2. A combination as in claim l, with a screen having a ilange interposed between the end of said screw stem and the adjoining end of said iilter pile retaining spring.

3. A combination as in claim 1, with a screen having a ange interposed between the end of said screw stem and the adjoining end of said iilter pile retaining spring, a check valve within the cover and a check valve closing spring having a bearing against said screen.

4. A combination as in claim 1. in which the casing has an entrance with a check valve seat and in which a spring closed check valve cooperates with said seat.

5. A combination as in claim 1, with a spring closed check valve at one end of the casing and a capillary tube connected with the opposite end of the casing.

6. A nlter unit, comprising a casing having a screw cover provided with a check valve seat, said casing having a seat opposite said check valve seat, a pile of looselyretained iilter leaves engaged at one end with said casing seat, a ball valve engaged with the check valve seat in the cover and a spring interposed between said ball valve and the adjoining end of the iilter pile.

ALFRED MUNOZ. 

